Question 1

All known porins are _____ proteins composed of _____.

Accepted Answer

A)  monomeric; seven transmembrane  $\alpha$ -helices 
B)  dimeric;  $\beta$ -barrels 
C)  dimeric; three transmembrane  $\alpha$ -helices 
D)  trimeric;  $\beta$ -barrels 
E)  trimeric; four transmembrane  $\alpha$ -helices 
A)  monomeric; seven transmembrane  $\alpha$ -helices 
B)  dimeric;  $\beta$ -barrels 
C)  dimeric; three transmembrane  $\alpha$ -helices 
D)  trimeric;  $\beta$ -barrels 
E)  trimeric; four transmembrane  $\alpha$ -helices

Question 2

The GLUT proteins have little structural resemblance to other transport proteins despite having a similar mechanism of transport.

Accepted Answer

A) True 
 B)False

Question 3

Nerve cells contain high levels of _____ which is a derivative of _____.

Accepted Answer

A)  phosphatidylethanolamine; palmitic acid 
B)  cholesterol; isoprene 
C)  phosphatidylcholine, phosphatidic acid 
D)  sphingomyelin; sphingosine 
E)  ganglioside GM1; ceramide 
A)  phosphatidylethanolamine; palmitic acid 
B)  cholesterol; isoprene 
C)  phosphatidylcholine, phosphatidic acid 
D)  sphingomyelin; sphingosine 
E)  ganglioside GM1; ceramide

Question 4

The Na,K-ATPase is a(n) _____ that moves Na+ from _____ and K+ from _____.

Accepted Answer

A)  antiporter; inside to out; outside to in 
B)  antiporter; outside to in; inside to out 
C)  symporter; inside to out; inside to out 
D)  symporter; outside to in; outside to in 
E)  none of the above 
A)  antiporter; inside to out; outside to in 
B)  antiporter; outside to in; inside to out 
C)  symporter; inside to out; inside to out 
D)  symporter; outside to in; outside to in 
E)  none of the above

Question 5

D-Glucose and D-Mannitol are similarly soluble, but D-Glucose is transported through the erythrocyte membrane four times as rapidly as D-Mannitol. What is the most likely explanation?

Accepted Answer

A)  D-Glucose undergoes simple diffusion more rapidly than D-Mannitol because glucose is less polar. 
B)  D-Glucose and D-Mannitol enter the erythrocyte via an ion-gated channel. 
C)  D-Glucose and D-Mannitol are transported via a system that distinguishes the two sugars. 
D)  D-Glucose flux through the membrane is linear, whereas D-Mannitol flux is described by a hyperbolic curve. 
E)  None of the above provides the explanation. 
A)  D-Glucose undergoes simple diffusion more rapidly than D-Mannitol because glucose is less polar. 
B)  D-Glucose and D-Mannitol enter the erythrocyte via an ion-gated channel. 
C)  D-Glucose and D-Mannitol are transported via a system that distinguishes the two sugars. 
D)  D-Glucose flux through the membrane is linear, whereas D-Mannitol flux is described by a hyperbolic curve. 
E)  None of the above provides the explanation.

Question 6

The GLUT transporters have a 12-stranded  $\beta$ -barrel structure that spans the membrane of the cell.

Accepted Answer

A) True 
 B)False

Question 7

The two conformational states of the GLUT proteins are ___ thus glucose ___.

Accepted Answer

in equilibrium, can

All known porins are _ proteins composed of _.

The GLUT proteins have little structural resemblance to other transport proteins despite having a similar mechanism of transport.

Nerve cells contain high levels of _ which is a derivative of _.

The Na,K-ATPase is a(n) ___ that moves Na⁺ from _ and K⁺ from ___.

D-Glucose and D-Mannitol are similarly soluble, but D-Glucose is transported through the erythrocyte membrane four times as rapidly as D-Mannitol. What is the most likely explanation?

The GLUT transporters have a 12-stranded $\beta$ -barrel structure that spans the membrane of the cell.

The two conformational states of the GLUT proteins are _ thus glucose _.

The Chemical Basis of Life

Aqueous Chemistry

Nucleic Acid Structure and Function

Protein Structure

Protein Function

How Enzymes Work

Enzyme Kinetics and Inhibition

Lipids and Membranes

Signaling

Carbohydrates

Metabolism and Bioenergetics

Glucose Metabolism

The Citric Acid Cycle

Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Nitrogen Metabolism

Regulation of Mammalian Fuel Metabolism

DNA Replication and Repair

Transcription and RNA

Protein Synthesis

Filters

Exam 9: Membrane Transport

All known porins are _____ proteins composed of _____.

The GLUT proteins have little structural resemblance to other transport proteins despite having a similar mechanism of transport.

Nerve cells contain high levels of _____ which is a derivative of _____.

The Na,K-ATPase is a(n) _____ that moves Na+ from _____ and K+ from _____.

D-Glucose and D-Mannitol are similarly soluble, but D-Glucose is transported through the erythrocyte membrane four times as rapidly as D-Mannitol. What is the most likely explanation?

The GLUT transporters have a 12-stranded β\betaβ -barrel structure that spans the membrane of the cell.

The two conformational states of the GLUT proteins are ___ thus glucose ___.

The Chemical Basis of Life

Aqueous Chemistry

Nucleic Acid Structure and Function

Protein Structure

Protein Function

How Enzymes Work

Enzyme Kinetics and Inhibition

Lipids and Membranes

Signaling

Carbohydrates

Metabolism and Bioenergetics

Glucose Metabolism

The Citric Acid Cycle

Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Nitrogen Metabolism

Regulation of Mammalian Fuel Metabolism

DNA Replication and Repair

Transcription and RNA

Protein Synthesis

Filters

All known porins are _ proteins composed of _.

Nerve cells contain high levels of _ which is a derivative of _.

The Na,K-ATPase is a(n) ___ that moves Na⁺ from _ and K⁺ from ___.

The GLUT transporters have a 12-stranded $\beta$ -barrel structure that spans the membrane of the cell.

The two conformational states of the GLUT proteins are _ thus glucose _.